Electrical apparatus



March 3, 1953 R. M. PURDY 2,630,462

ELECTRICAL APPARATUS Filed Dec. 5, 1949 2 Sl-lEETSSl-IEET 1 IN VEN TOR.

ale Q. 6 ATTO/P/VAY March 3, 1953 R. M. PURDY ELECTRICAL APPARATUS 2SI-lEETS-SHEET 2 Filed Dec. 5, 1949 mmvron. W 772. fwd? Tic. E.

Patented Mar. 3, 1953 UNITED STATES PATENT OFFICE ELECTRICAL APPARATUSRolland M. Purdy, Bainbridge, N. Y., assignor to Bendix AviationCorporation, New York, N. Y., a corporation of Delaware ApplicationDecember 5, 1949, Serial No. 131,074

11 Claims.

This invention relates to electrical apparatus and more particularly tomeans for generating and distributing periodic impulses of high voltageelectrical energy.

One of the objects of the present invention is to provide a novelmagneto generator of a highly versatile nature that may be readilyadapted for use in the ignition ystems of a wide variety of engines.

Another object of the invention is to provide a device of the abovecharacter wherein the parts are assembled and drivably and electricallyconnected with one another in. a novel manner which facilitatesdisassembly, re-assembly, and inspection thereof.

A further object is to provide in ignition apparatus a novel andsimplified combination of a plurality of rotating parts, such as acircuit breaker cam, a magnetic flux distributing rotor, and anelectrical current distributing rotor.

A still further object is to provide novel electrical connecting meansfor transmitting electrical energy.

Still another object is to provide novel means for mounting the rotatingelements of an ignition distributor or the like on a rotating shaft forrotation therewith.

The above and further object and novel features of the invention willmore fully appear from the following detailed description when the sameis read in connection with the accompanying drawings. It is to beexpressly understood, however, that the drawings are for the purpose ofillustration only and are not intended to define the limits of theinvention.

In the drawings, wherein like reference characters refer to like partsthroughout the several iews,

Fig. 1 is a side view, mostly in section, of one form ofmagneto-distributor embodying the present invention;

Fig. 2 is an isometric exploded view of the circuit breaker cam anddistributor finger assembly of the device of Fig. 1;

Fig. 3 is a partial end view of the distributor finger as viewed fromthe right in Figs. 1 and 2;

Fig. 4 is an enlarged detail view, partly in section and with partsbroken away, showing part of the means for conducting energy from thetransformer coil;

Fig. 5 is a detail end view of the spring and mounting member thereforshown in Fig. 4;

Fig. 6 is a detail sectional view, taken substantially on line 6-6 ofFig. 7;

Fig. 7 is an enlarged detail view of a contactor plate, taken on line1-1 of Fig. 4;

Figs. 8 and 9 are end and sectional views, respectively, of a singlelobe circuit breaker cam, the section of Fig. 9 being takensubstantially on line 9--9 of Fig. 8; and

Figs. 10 and 11 are end view similar to Fig. 8 of interchangeablecircuit breaker cams having two and four lobes, respectively.

The single embodiment of the invention illustrated in the drawing, byway of example, is shown in the form of a combined magneto generator andignition distributor ior supplying electrical energy to the spark plugsof an internal combustion engine or the like. As shown, the workingparts are enclosed and supported in a. simple two-part housingcomprising a body porticn l0 and a cover ll suitably secured thereto.Rotatably supported in housing body It is a magnetic rotor l2 that maybe of any suitable known construction. As shown, the rotor comprisespermanent magnets l4 and four equally spaced laminated pole shoes l5supported on a flanged hub member 16. The rotor is supported on andkeyed to a shaft I! for rotation therewith. The right hand end of theshaft, as viewed in the drawings, is supported by a suitable bearing(not shown) in the end wall of easing member [0, and the other end issupported by a roller bearing l8 which is in turn mounted in asupporting bracket [9 that is removably secured in position against ashoulder 20 by stud bolts 2| (only one being shown) to therebyfacilitate assembly and disassembly with a minimum of parts. Power maybe transmitted to rotor l2 from the engine through an impulse coupling22 that may be of any suitable knownv construction. Housing [0, ll maybe secured to the engine casing for angular adjustment about the axis ofrotor [2 by means of stud bolts (not shown) which project from theengine casing through arcuate slots 9 in a flange on the housing or fromarcuate slots on an engine casing flange (not shown).

The rotor cooperates in the usual well known manner with laminatedstator poles 23, 24 which are cast in the opposite side walls of casing.I0 or otherwise suitably secured therein by means of rivets or the like.The upper ends of the stator poles are magnetically connected by alaminated core 25 on which is wound the windings of a transformer coil26. The coil and core are secured in position in a known manner by screwand spring sets 21, 28 which engage the upper surfaces of the core nearthe ends thereof.

Mounted in a novel manner on the reduced inner or left end of rotorshaft I! for rotation therewith is a circuit breaker cam 29 and anelectrode-carrying distributor finger or rotor 30.

The mounting of these parts is such as to render the magneto readily andquickly adaptable for either right hand or left hand rotor rotation andfor use with engines having one, two or four cylinders. As shown, thecam 29 is in the form of a sleeve having a sliding fit on the end ofshaft H to which it is attached for rotation by a key 3|. The borethrough cam sleeve 29 is slightly enlarged adjacent each end to forminternal shoulders 32, 33, for a purpose to more fully appear hereafter.One end of the cam sleeve is provided with a segmental fiat 33 and theother end with a similar fiat 34, the planes of said flats making anangle of about 45 with each other in the embodiment illustrated. Whenthe cam is in place on shaft I! one end engages the inner race ofbearing l8, and the shoulder 32 in the other end is in a plane justslightly beyond the end of shaft I1. The flats on the cam are used inproperly timing the magneto to the engine. This is done by aligning theflat with a timing mark on the housing when the latter is installed onthe engine.

Cam sleeve 29 is secured against axial movement on shaft I! by a novelstub shaft 35, the threaded reduced portion of which engages a threadedrecess in the end of the shaft. The cam is thus held in place by theshoulder 36 on the stub shaft between which and shoulder 32 of the camare interposed a plain washer 31, a lock washer 38, and the web 39 of abifurcated spring member 40.

The outer enlarged end of stub shaft 35 serves as a support fordistributor finger or rotor 36 which is preferably made of moldedinsulating material and provided with a recess 4! for slidably receivingthe shaft. Novel means comprising spring member 40 is provided tocompensate for the necessary tolerances between the diameters of shaftextension 35 and recess 4|, and to thereby minimize chattering orvibration of the rotor during operation. For this purpose shaftextension 35 has oppositely disposed longitudinally extending grooves 42cut therein for receiving the fiat leaf spring arms of member 46 whenthe web 39 of the latter engages shoulder 36. Central portions 43 ofsaid spring arms are arched to resiliently engage the inner surface ofrecess 4| and thereby provide a suitably tight fit between the rotormember and the shaft. Except for the arches or bends 43 the sizes andshapes of grooves 42 and the spring arms are such that there will be nointerference with rotor member 30 when the same is installed. Althoughtwo grooves 42 and cooperating spring arms are shown, one or more thantwo may be provided.

Distributor rotor 30 is angularly located and positioned in a novelmanner with respect to cam 29 and hence, with respect to magnetic rotorl2. The novel means for thus positioning the distributor rotor alsoeffects a driving connection for transmitting torque thereto from thecam which is in turn keyed to the shaft l1. As shown, rotor member 30has an axial projection with a flat surface 44 that engages the flat 33or 34 on cam 29 depending upon which way the reversible cam isinstalled. This permits use of the magneto for either right or left handrotor rotation without changing any of the parts, the change from one tothe other being accomplished by mere reversal of cam sleeve 29 on shaftIT. The various parts are so constructed that they must of necessity beproperly assembled.

Although the spring loop 43, 43 tend to resist axial movement ofdistributor rotor 30 on shaft extension 35, novel means are provided forpositively securing the same against such movement, said means beingreadily applied and removed irrespective of the relative positions ofthe rotor and the shaft. The latter is provided with an annular groove45 which is preferably deeper than grooves 42. When rotor 39 is inproper axial position on the shaft, one or more transverse holes 46 inthe hub 49 of rotor 30 register with groove 45 for receiving thestraight portion 41 of a locking spring or pin which has a holding orretaining portion 48 bent back upon the portion 41 and shaped to engagethe outer cylindrical contour of hub 49 to thereby resiliently hold thelocking pin in installed position and yet permit relatively easywithdrawal thereof for purposes of disassembly.

A circuit breaker (not shown) of any conven tional or suitable designmay be mounted on bracket or semi-partition [9 in the half of casing II]which is removed by the section in Fig. 1. This circuit breaker issuitably positioned for periodic operation in the usual manner by cam29. A portion only of the circuit breaker mounting plate is shown at 59.A complete showing of the circuit breaker is believed to be unnecessaryin view of the fact that the construction thereof may be conventionaland does not, per se, constitute any part of the present invention.

Distribution rotor 39 has secured thereto an electrode 5| which duringrotation periodically moves into spark gap relation with an outputelectrode 52. The latter is suitably insulated and associated with onehalf 53 of a plug and socket type connector removably mounted in coverH. A suitable conducting lead may be provided be tween connector part 53and the spark plug of an engine. If the engine on which the magneto isused has a plurality of cylinders, such as two or four, additionaloutput electrode-connector combinations 54 similar to the part 52, 53may be provided. The output electrodes are equally spaced from eachother on a circle with its center at the axis of rotor 30 so that rotorelectrode 5| will move successively into spark gap relation therewith.

Rotor electrode 5i is operatively connected with the secondary orhigh-voltage winding of coil 26 by novel means mounted in cover I I. Inthe form shown said means comprise an insulating block 55 secured insideof the cover by some suitable means such as a plurality of stud bolts 56and extends across the axis of shaft IT. The electrical connection fromelectrode 5| to the coil is through a spring contact 51 which yieldablyengages a button 58 molded in block 55 and connected by a conductor 59to a contact 60 also molded in block 55 at the inner end of a recess 6!.This contact is preferably connected to the coil through a spring 62, aresistor 63, a spring 64 novelly mounted on block 55, and a contactwasher 65 secured in a novel manner to a ribbontype conductor 66 thatemerges from the side of the coil.

Coil spring 64 is novelly mounted on block 55 for automatic contact withwasher 65 when cover H is put in place. The mounting means consists ofan anchoring member 6! which is best seen in Figs. 4 and 5. Said membermay be fabricated from a flanged metallic tube 68 by rolling a marginalend portion thereof outwardly and forming a head 69 over the endconvolution of the spring. The flange at the other end of the tube iscut to form spaced portions that are then curled outwardly to formresilient tongues ga e in. When member 61, thus formed, is pressed intoan enlarged portion of recess 6! against a shoulder ll, tongues arebiased outwardly against the wall of the recess so that the cornersthereof bite into the surface of the recess and resist withdrawalthereof.

The ribbon conductor 66 which emerges from coil 26 and represents thehigh potential end of the secondary winding thereof is passed through aslot 73 in washer E5 and locked therein in a novel manner. Said slot isoriginally rectangular in shape and is deformed by staking the washerwith a suitable tool at 72, 72 (Fig. 7) to reduce the width of slot i3at one face of the washer and, hence, provide opposed lips which effecta biting action against opposite surfaces of the conductor 86 to preventremoval of the washer therefrom. Lips 75 are sufilciently flexible topermit easy installation of the washer in the direction of the arrow inFig. 6 but bite into the conductor when the direction of movement isreversed.

As heretofore pointed out it is only necessary to reverse the cam member29 on shaft ll, i. e., turn it end for end, for changing the magnetofrom counter-clockwise operation to clockwise operation. To adapt themagneto to engines with one, two, or four cylinders, it is onlynecessary to use a cam having one, two, or four properly positionedlobes, respectively, as shown in Figs. 8, l0, and 11. The single lobecam 29 of Fig. 8, for example, will operate the circuit breaker onceduring each revolution of the rotor shaft at a time when electrode Si isadjacent the single output electrode 52. The two-lobe cam 29' of Fig. 10and the four-lobe cam 29" of Fig. 11 will operate the circuit breakertwice of four times, respectively, during each cam revolution at timeswhen electrode 5! is adjacent the additional output electrodes installedin cover ll in the manner heretofore explained. Coil 26 has the primarywinding thereof connected in a conventional manner with the circuitbreaker across which is connected a condenser 16 also supported by thepartial partition 59. As is well understood in the art, a high voltageis induced in the secondary winding of the coil each time the circuitbreaker is opened to interrupt the circuit of the primary winding. Thissecondary voltage is impressed across the gap 5|, 52 and, hence, uponthe spark plug to which electrode 52 is connected.

The casing if), H is preferably dust-proof, ventilation being providedthrough suitable filters T1. The filters shown are of known type andcomprise stacks of thin wavy washers i8 sur-- rounding a duct 19 in thecasing member H.

There is thus provided a novelly constructed magneto-distributor adaptedfor use in internal combustion engine ignition systems and havingconsiderably greater versatility than similar devices heretoforeprovided for the same purpose. Considering the capabilities of thedevice, the number of parts have been reduced to a minimum of readilyaccessible parts, and the novel features of the construction greatlyfacilitate assembly and disassembly of such parts. The several noveldetails of construction herein described contribute to the over-allefficiency and simplicity of the complete device and particularly to theease with which inspections of the vital parts and adaptations fordifferent engines may be accomplished.

Although only a limited number of embodiments of the invention areillustrated in the accompanying drawings and foregoing description,

it is to be expressly understood that the inven-' tion is not limitedthereto. In addition to the modifications hereinabove suggested, variousadditional changes may be made in the design and arrangement of partsillustrated without departing from the spirit and scope of the inventionas will now be understood by those skilled in the art. For example, thecam 29 may be positioned on shaft I? by means of a shoulder on thelatter in lieu of engagement with the inner race of bearing 18.

What is claimed is:

1. In electrical apparatus of the class described, a housing comprisinga body member and a cover for the open face of said member, a partialpartition removably secured across the open face of said body member, amagnetic flux distributing rotor comprising a shaft journalled in thewall of said body member and said partition, a pair of stator poles insaid body member operativcly associated with said rotor, a transformercoil having a core magnetically connecting said stator poles, a circuitbreaker mounted on said partition, a cam slidably mounted on the rotorshaft for rotation therewith to actuate said circuit breaker, a stubshaft having a reduced portion threaded into a recess in the end of Saidrotor shaft for securing said cam against axial movement on the latter,a distributor finger slidably mounted on said stub shaft, radiallybiased resilient means interposed between said stub shaft and theinterior of said finger, the latter having an eccentric fiat surfaceengaging an eccentric fiat surface on said cam for positioning thefinger relative to the cam and for rotatably connecting the same, meansfor holding said finger against axial movement on the stub shaftincluding a pin extending through an opening in the hub of said fingerand a circumferential groove in said stub shaft, at least one outputelectrode removably mounted in said cover, an electrode mounted on saidfinger adapted during rotation of the latter to periodically move intospark gap relation with said output electrode, means mounted in saidcover for electrically connecting said finger electrode to the highpotential end of the secondary winding of said coil, said connectingmeans including conducting means in an insulating block having a recess,a spring and a metallic tube having resilient laterally extendingtongues thereon for securing one end of said spring in said recess, anda slotted plate adjacent said coil and having a biting engagement with aribbon conductor constituting the end of the secondary winding, saidplate being engageable by said spring when the cover is installed.

2. In a magneto generator a housing comprising a body member and a coverfor the open face of said member, a partial partition removably securedin said body member across the lower portion thereof, a magnetic fluxdistributing rotor comprising a shaft journalled in the wall of saidbody member and said partition, a pair of stator poles in said bodymember operatively associated with said rotor, a coil having a coremagnetically connecting said stator poles, whereby electrical energy isinduced in said coil during rotation of said rotor, a circuit breaker incircuit with the coil and mounted on said partition, a cam slid-ablymounted on the rotor shaft for rotation therewith to actuate the circuitbreaker, a stub shaft having a reduced portion threaded into a recess inthe end of said rotor shaft for securing the cam against axial movementon the latter, and a distributor finger mounted on said stub shaft andhaving operative engagement with said cam, whereby the finger ispositioned relative to the cam and rotatably connected therewith.

3. In ignition apparatus, such as a magneto generator, a rotatableshaft, a cam mounted on said shaft for rotation therewith, a distributorfinger slidably mounted on said shaft and having direct drivingengagement with said cam, and means for fixing said finger against axialmovement on said shaft including a pin extending through both a portionof said finger and a portion of a circumferentially extending groove insaid shaft.

4. Apparatus as defined in claim 3 including radially biased resilientmeans interposed between said shaft and the adjacent surface of thedistributor finger to resist radial movement of the finger relative tothe shaft.

5. In apparatus of the class described a rotatable shaft having anaxially extending groove and :a circumferentially extending groove, amember having a recessed hub slidably mounted on said shaft around saidgrooves, resilient means in said axially extending groove and biasedradially outward against the inner surface of said hub, means forholding said member against axial movement on said shaft, said holdingmeans including a pin extending through both a portion of said hub and aportion of said circumferentially extending groove and a spring armextending from said pin and engaging the outer periphery of said hub forresisting withdrawal of said pin, and means for drivably connecting saidmember to said shaft for rotation therewith.

6. In a magneto generator, 21. housing comprisin a body member and acover for the open face of said member, a coil mounted in said bodymember, means for inducing electrical energy in said coil including arotatable shaft, a distributor finger mounted on said shaft having anelectrical contact at the axis of rotation thereof, and insulatedconductor means mounted wholly within said housing on said cover forelectrically connecting said contact with said coil when said cover isoperatively mounted on said body member, said last named meanscomprising an insulating block having a recess therein, a coil springextending from the recess to a terminal of the coil and means forfastening one end of the spring in said recess, said fastening meansbeing constituted by a tubular member operatively secured to one end ofthe spring and having a plurality of outwardly curved spring fin gersengaging the walls of said recess under radial compression.

7. Apparatus as defined in claim 6 wherein the coil terminal comprises awasher having a .slot therein, and a flat conductor extending throughthe slot, the sides of said slot at one face of the washer being pressedtogether against the conductor to exert a biting action thereon andresist removal of the washer from the conductor.

8. In electrical apparatus, a terminal compris ing a washer having aslot therethrough, and a conductor extending through said slot, thesides of the latter being bent inwardly at one face of the washer intobiting engagement with the conductor to resist movement of the washeralong the conductor in one direction While permitting movement thereofin the other direction.

9. In a, magneto generator, a four-pole magnetic rotor, a two-polestator mounted in operative relation with said rotor, a coil having acore connecting said stator poles, a circuit breaker in circuit withsaid coil, a single lobe cam mounted on the shaft of said rotor forrotation therewith to operate said circuit breaker, a distributor fingermounted on said shaft and having means engageable with said cam fordrivably connecting and relatively positioning the same, said cam beingreversible on the shaft for different directions of rotation thereof, acontact on said distributor finger, means for electrically connectingsaid contact with said coil, and a single output terminal mounted forcooperation with said distributor finger contact once during eachrevolution thereof.

10. Apparatus as defined in claim 9 wherein the cam has two oppositelydisposed lobes and wherein there are two output terminals disposed ondiametrically opposite sides of the axis of rotation of the distributorfinger for successive cooperation with said distributor finger contact.

11. Apparatus as defined in claim 9 wherein the cam has four equallyspaced lobes and wherein there are four output terminals equally spacedaround the axis of rotation of the distributor finger for successivecooperation with said distributor finger contact.

ROLLAND M. PURDY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,588,546 Gilchrist June 15, 19261,886,566 Mallory Nov. 8, 1932 1,933,304 Bell Oct. 31, 1933 2,013,335Beeh Sept. 3, 1935 2,016,669 Davis Oct. 8, 1935 2,144,218 Dunham Jan.17, 1939 2,198,892 Twining et al Apr. 30, 1940 2,228,138 Larkin Jan. 7,1941 2,430,831 Simmons Nov. 11, 1947 2,502,539 Tinnerman Apr. 4, 1950

